Telecommunications equipment can include a connector chassis and multiple line cards that are connected to the connector chassis. Each line card can be configured to perform a corresponding operation according to prescribed customer specifications. For example, one line card can be implemented as a network router device having a wide area network interface circuit connector, another as a firewall device, another as a local area network switch, another as a line interface having one or more network interface circuit connectors (e.g., 100-Base T, 1000-Base T, ATM OC-3, etc.).
A particular concern of using a connector chassis with multiple line cards involves enabling the removal of a line card from the connector chassis without affecting operations of the other line cards connected to the connector chassis. A particular concern is the ability to shut down network traffic on the line card before removal of the line card: a failure to shut down network traffic on the line card before removal from the connector chassis can cause a failure in other hardware devices (or software programs executed on the hardware devices) that expect the continued availability of the network traffic from the line card. One attempt to detect removal of the line card relied on long and short sense pins installed on the line card, where during removal of the line card the short sense pin (having a length of about 1 to 2 mm) would be disconnected from the connector chassis before the long sense pin (having a length of about 3 mm): network traffic shutdown on the line card would be initiated in response to the line card detecting the disconnect of the short sense pin from the connector chassis. However, the time interval between the disconnect of the short sense pin and the long sense pin was dependent upon the speed at which the user removes the line card: hence, the failure to shut down network traffic on the line card before removal still could occur if the user removed the line card too quickly.